Wrack mostly consists of the kelp that washes onto beaches from the ocean. Wrack is an essential part of the ecology of the shoreline, providing food and habitat for everything from insects to birds.

Santa Rosa Island - total

Figure App.E.10.11.. A figure showing the composition of “beach wrack” (decaying large seaweed washed up on shore) on Santa Rosa Island from 1995 - 2015.

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Macrophyte beach wrack percent cover at Santa Rosa Island is shown by species. Wrack primarily consists of Macrocystis (Giant kelp) or Phyllospadix (surf grass); however these two key types of wrack show recent decreases in percent cover. Figure: Channel Islands National Park

Santa Rosa Island - per site

Figure App.E.10.12.. A figure showing the composition of “beach wrack” (decaying large marine plants washed up on shore) across nine beaches on Santa Rosa Island from 1995 - 2015.

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Macrophyte wrack species composition at eight sites on Santa Rosa Island. Wrack primarily consists of Macrocystis pyrifera (giant kelp) and Phyllospadix (surf grass) which varies from 0 to > 50% coverage; however, these two key wrack types show recent decreases in percent cover. Figure: Channel Islands National Park